Deactivation of nickel methanation catalysts induced by the decomposition of iron carbonyl. I. Deactivation via pore-month blocking
The deactivation of alumina-supported nickel methanation catalysts due to decomposition of Fe(CO)/sub 5/ was studied using both reaction kinetics measurements and in situ Moessbauer spectroscopy. Iron carbonyl, enriched in /sup 57/Fe for Moessbauer spectroscopy studies, was produced in situ and entrained with the carbon monoxide feed to a methanation reactor operating at temperatures of 620 to 650 K and H/sub 2//CO ratios near 7. This incorporation of Fe into the nickel catalyst via the decomposition of Fe(CO)/sub 5/ resulted in significant catalyst deactivation as well as changes in the parameters of a power law rate expression describing the methanation kinetics. With increasing amounts of Fe deposited on the catalyst, the kinetic parameters were shifted toward those of iron catalysts. These iron-induced phenomena are due to (1) pore-mouth blocking of the Al/sub 2/O/sub 3/ micropore structure by iron particles formed during the diffusion-limited decomposition of Fe(CH)/sub 5/, and (2) interactions between iron and nickel in the macropores of the support. Specifically, the loss of catalyst activity is primarily caused by pore-mouth blocking, while shifts in kinetic parametsrs are the consequence of both pore-mouth blocking and interactions between iron and nickel. The majority of the iron deposited under methanation reaction conditions has been identified as chi-carbide (Haegg carbide) using Moessbauer spectroscopy at liquid helium temperature. 55 references, 7 figures, 4 tables.
- Research Organization:
- Univ. of Wisconsin, Madison
- DOE Contract Number:
- FG21-78ET12248
- OSTI ID:
- 5354728
- Journal Information:
- J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 84:1; ISSN JCTLA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
10 SYNTHETIC FUELS
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
400301 -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ABSORPTION
ACTIVATION ENERGY
ALKANES
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CARBIDES
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CARBONYLS
CATALYST SUPPORTS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
COMPUTERIZED SIMULATION
CORRELATIONS
CRYSTAL DOPING
DATA
DEACTIVATION
DECOMPOSITION
ELEMENTS
ENERGY
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
FLUIDS
GASES
HIGH TEMPERATURE
HYDROCARBONS
HYDROGEN
INFORMATION
INTERMEDIATE MASS NUCLEI
IRON 57
IRON CARBIDES
IRON COMPOUNDS
IRON ISOTOPES
IRON OXIDES
ISOTOPES
KINETICS
LOW PRESSURE
MEDIUM PRESSURE
MEDIUM TEMPERATURE
METALS
METHANATION
METHANE
MOESSBAUER EFFECT
NICKEL
NONMETALS
NUCLEI
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PARTIAL PRESSURE
PRESSURE DEPENDENCE
REACTION INTERMEDIATES
REACTION KINETICS
SIMULATION
SORPTIVE PROPERTIES
STABLE ISOTOPES
SURFACE PROPERTIES
SYNTHESIS GAS
TEMPERATURE DEPENDENCE
TIME DEPENDENCE
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
ULTRALOW TEMPERATURE
YIELDS